This application claims priority to German Patent Application No. 10145012.5 filed Sep. 12, 2001, which application is herein expressly incorporated by reference.
The invention relates to a drive assembly, and especially for agricultural implements with driven rotating masses.
In the driveline of agricultural implements pulled by a tractor, driven by the tractor power take-off shaft or are in self-propelled agricultural implements, different functional parts of the implement are driven by a branched drive system that starts from a central drive. In order to avoid any overloading, the drive systems are provided with couplings.
In some functional areas where there is a risk of clogging, it is necessary to remove the material causing the clogging. In such a case, the operative either has to reverse the drive and if such an action does not release the obstruction, the operative must manually remove the clog while the machine is still in operation. Therefore, the drive first has to be stopped.
It is an object of the present invention to propose a drive assembly where the drive can be disconnected either manually or by an actuating device.
In accordance with the invention, a drive assembly has a shear pin coupling defining a longitudinal axis. A coupling hub is provided with a seat face and a bearing seat. A first projection with reference to the longitudinal axis projects radially from the seat face. A first attaching means is included. The seat face is axially arranged between the first projection and the bearing seat. A coupling sleeve is supported on the bearing seat of the coupling hub and is rotatable relative thereto. A second projection extends radially relative to the longitudinal axis. A second attaching means has a ratchet gear which is supported on the seat face of the coupling hub by a bearing bore to be rotatable relative thereto. At least one holding face is present. A shear pin is received in receiving bores of the first projection, second projection and ratchet gear. The bores are aligned relative to one another. The shear pin firmly connects the projections in the direction of rotation around the longitudinal axis. The receiving bores are arranged to be radially offset relative to the longitudinal axis. A locking device with a locking element is held in an inactive position. The locking device can be displaced manually, either directly or via an actuating device, out of the inactive position into contact with the holding face of the ratchet gear. This stops the rotational movement of the ratchet gear.
The solution in accordance with the invention provides a drive assembly that uses a shear pin coupling for disconnecting, by an outside external action, the drive from the functional part of the driven implement. This can be effected manually by a release cord or a lever arrangement. The locking element of the locking device is displaced from the inactive position into the active position to contact the holding face of the ratchet gear. The release cord may be a Bowden cable, for example, on the locking element. However, it is also possible to select a different actuating device which automatically releases a locking function, for example, when a cover in an agricultural implement is opened. The transmission of torque can deliberately be restored only by inserting a new shear pin. The measures in accordance with the invention make it possible to provide a prior art shear pin coupling additionally with a disconnecting function.
According to a further embodiment of the invention, the bearing seat of the coupling hub includes a first running groove which receives bearing balls. The coupling sleeve, via a second running groove, is rotatably supported around the longitudinal axis relative to the coupling hub. This ensures that the relative movement between the coupling hub and the coupling sleeve is of the low-friction type.
In a preferred embodiment, the holding face is formed by a projection provided on the circumference of the ratchet gear. Preferably, a plurality of holding faces are on the circumference of the ratchet gear in order to keep the reaction time as short as possible.
An advantageous embodiment includes the locking element as a locking ratchet held by a spring in the inactive position. The locking ratchet is pivoted against the force of the spring, so that, via a locking face, it comes into contact with the holding face. The locking ratchet is arranged such that the forces which are introduced into the locking ratchet, as a result of abruptly stopping of the ratchet gear, are directly introduced into the pivot bearing so that the locking ratchet cannot escape.
Instead of actuating the locking ratchet manually via a suitable lever drive, Bowden cable or by cable control, it can be actuated by a power drive. The power drive can be controlled by a sensor. When an operative places his hand into the region of the machine, the power drive records such an action as a releasing criterion. In a preferred embodiment, the shear pin is a headed screw with a nut. The shear pin connects the coupling sleeve, the coupling hub and the ratchet gear firmly to one another and is radially offset and arranged parallel relative to the longitudinal axis. Depending on the type of application, the first attaching mechanism is a profiled bore in the coupling hub. The bore is centred on the longitudinal axis. Also, the first attaching mechanism may be a flange connected to the coupling hub. The bore includes teeth to enable a connection with a corresponding profiled journal. Where the drive assembly is to be integrated into a driveshaft drive system, the second attaching mechanism is a joint yoke of a universal joint or a flange.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.